This invention relates to an apparatus for oxygenating a liquid, such as water, a method for oxygenating the liquid, and applications of liquids oxygenated by the inventive apparatus and method.
It is known that various types of liquids are oxygenated, i.e., prepared in solution with oxygen, to achieve various results. For example, consumption of an oxygen enriched beverage has a favorable effect on well being and physical performance. For example, eight test subjects of various ages and differing sex had their blood oxygen contents and their pulse rates determined. Each subject then drank between 1/2 and 3/4 liters of highly oxygenated water. A short period after ingestion of the enriched water, evidence of a pulmonary function bypass was observed through an average blood oxygen level increase of about 30%, and the effect of a concomitant cardiac relief was observed through an average pulse rate reduction of about 10%. Further, the added oxygen tends to reduce the tartness of any carbonation and does not impart any taste to the resulting liquid.
As a further example, a liquid may be oxygenated to promote bioremediation of contaminated or oxygen-depleted bodies of water, and effective bioremediation requires a high rate of oxygen use. The replenishment of oxygen in groundwater, for example, occurs very slowly. As a result, oxygen levels in the contaminated groundwater systems are often quickly depleted, even when water has been thoroughly aerated before the onset of the bioremediation process. Thus, bioremediation processes are more effective if higher oxygen levels are provided in the groundwater, enabling a desirably greater and more rapid treatment.
It is known to oxygenate still liquids (i.e., liquids which are substantially gas-free) at super-atmospheric pressure with oxygen from an external source. The impregnation of the liquid with gas is usually carried out in sealed vessels or conduits, with the impregnated liquid subsequentially transferred to bottles or other containers in which it is to be marketed, the bottles filled and sealed under super-atmospheric pressure in order to prevent, so far as possible, the escape of oxygen gas from the liquid. Moreover, it is known to intermix oxygen into liquids by passing the liquid through a venturi mixer or injector and introducing oxygen into the admixture at the venturi throat. Further, it is known that a shockwave may be produced in the diverging outlet of a venturi mixer or injector to promote mixing of the liquid and the gas. Generally, venturi mixers or injectors employed in liquid oxygenating apparatuses are oriented horizontally, or vertically and such that the liquid flow therethrough is upwardly directed.
Currently, one of the most effective known method and apparatus for saturating a liquid with oxygen on an industrial scale is described in published International Patent Application WO 97/27146 and U.S. Pat. No. 5,766,490. According to this process, a sealed enriching space is provided which includes a venturi mixer, through which liquid to be oxygenated upwardly flows, the oxygen gas introduced to the liquid in the venturi throat. This known method and apparatus works well, producing an oxygen-enriched liquid having at least 40 mg/l oxygen at a rate of approximately 50,000 gallons per day (gpd), but does not take full advantage of the mixing potential offered by a venturi mixer or injector. A method and apparatus providing greater oxygen concentrations and flow rates is desirable.
Further, a method and apparatus which can automatically control various aspects of the process of oxygenating a liquid with only the operator's input of a desired, variable oxygen concentration level would be desirable.